We examined the time -dependent donor decays of 2 - amino purine (2 -APU) , in the presence of increasing amounts of acceptor 2-aminobenzophenine (2-ABP). As the concentration of 2-ABP increases, the frequency-responses diverge from that predicted by Forster. The data were found to be consistent with modified Forster equations, but at this time we do not state that these modified expressions provide a correct molecular description of this donor-acceptor system. To the best of our knowledge this is the first paper which reports a failure of the Forster theory for randomly distributed donors and acceptors.